Alkylation of phenolic compounds catalyzed by friedel-crafts metal halides modified by boric acid



Patented Aug. 30, 1949 ALKYLATION OF PHENOLIC COMPOUNDS CATALYZED BY FRIEDEL-CRAFTS METAL HALIDES MODIFIED BY BORIC ACID Julian M. Mavity, Hinsdale, 11]., assignor to Universal Oil Products Company, Chicago, 111., a

corporation of Delaware No Drawing. Application June 19, 1948, Serial No. 34,150

18 Claims.

This application is a continuation in part of, my co-pending application, Serial No. 619,431, filed September 29,1,945, now Patent No.2,467,326.

This invention relates to the catalytic interaction of a phenolic compound with a compound capable of yielding a hydrocarbon radical. It is more particularly concerned with the production of alkyl phenols by reacting a phenol containing a hydrogen atom attached to the ring with an alkylating agent in the presence of a catalyst prepared by reacting boric acid and a metal halide of the Friedel-Crafts type.

The alkylation of phenols to produce mono and polyalkylphenols is an important reaction. in organic synthesis since the alkyl phenols not only possess utility as such but also because they are important intermediates in the preparation of inhibitors and the like. I have discovered that the alkylation of phenols may be accomplished with ease and efficiency if a particular type of catalyst is utilized.

In one embodiment my invention relates to a process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with an alkylating agent at alkylating conditions in the presence of a catalyst prepared .by reacting boric acid and a metal halide of the Friedel-Crafts type with the evolution of hydrogen halide.

In a more specific embodiment my invention relates to a process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with a monoolefin at alkylating conditions in the presence of a catalyst prepared by reacting boric acid and a metal halide of the Friedel-Crafts type with the evolution of hydrogen halide.

Phenolic compounds that may be reacted with alkylating agents in accordance with the process of this invention must contain at least one substitutable nuclear hydrogen atom, i. e., a hydrogen atom that is attached to the ring and that is capable of being replaced by a hydrocarbon radical, particularly an alkyl group. Examples of such compounds are phenol; cresol; polyhydric phenols such as hydroquinone and catechol; alkoxyphenols such as guiacol, paramethoxyphenol, and paraethoxyphenol, in which the number of carbon atoms in the alkyl group is small; naphthol; and the like.

Alkylating agents capable of yielding an alkyl group under the conditions of operation employed in the process are one type of compound capable of yielding hydrocarbon radicals that are utilizable in my process. Compounds of this type include both normally gaseous and normally liquid olefins, particularly olefins containing more than two carbon atoms per molecule. Such oleflns include propylene, iso and normal butylenes, 150

and normal amylenes, methylcyclohexene, and the like. Other alkylating agents include oycloparaffins containing three or four carbon atoms in the ring, mercaptans, mineral acid esters such as alkyl halides, and alkoxy compounds of the class consisting of aliphatic alcohols, and esters of carboxylic acids. In general the alkylating agents that are most easily reacted in my process comprise those in which the double bond or in which the substituent, such as the chlorine atom in alkyl chlorides, are attached to a tertiary carbon atom. Other compounds capable of yielding a hydrocarbon radical include diolefins and aromatic compounds in which a nuclear hydrogen atom has been replaced by an olefinic hydrocarbon radical. Examples of such aromatic compounds are styrene, alpha methyl styrene, and the like.

I have found that catalysts useful in promoting the condensation of phenolic compounds containing a substitutable hydrogen atom attached to the ring with compounds capable of yielding hydrocarbon radicals may be made by interacting boric acid with a metal halide of the Friedel- Crafts type under such conditions that limited amounts of hydrogen halide are evolved, which amounts generally are from about 0.5 to about 2.0 molecular equivalents based upon the metal halide. It is apparent that since there are a number of Friedel-Crafts type metal halides which may be interacted, a considerable number of alternative catalysts may be made although such catalysts will not necessarily be equivalent in their action. Friedel-Crafts type metal halides which may be reacted with boric acid to form catalysts useful in the present process include aluminum chloride, aluminum bromide, zinc chloride, zirconium chloride, ferric chloride, antimony chloride, bismuth chloride, and others. Substantially anhydrous aluminum chloride is the Friedel-Craits type catalyst usually employed in the alkylation of phenols. However. disadvantages accompany its use in some instances on account of its high degree of activity. Thus, it has a tendency to form undesirable complexes with unsaturated and phenolic compounds. However, by reacting proportioned mixtures of an. aluminum halide, such as aluminum chloride, and boric acid in accordance with the present invention, catalysts of modified activities are obtained which may be utilized for promoting the alkylation of phenolic compounds as herein set forth. These catalysts do not form substantial amounts of complexes with unsaturated and aromatic hydrocarbons and, accordingly, they may be used in continuous processes over long periods of time with relatively little contamination by such complexes so that in many instances the catalyst life is considerably longer than the life of the corresponding aluminum halide in similar types of reactions. An additional advantage of these catalysts is that their solubility in the products of this reaction is considerably less than that of gen pressure of 20 atmospheres. The nitrogen was present to prevent sublimation oi the aluminum chloride before it had time to react with boric acid. The material recovered from the I 1.0 gm. estimated as weight or henol. 8 Converted from readings at in icated pressures.

metal halide, such as aluminum chloride and liner weighed 124.63 grams; 12.06 grams of the aluminum bromide, and thus the usual step of starting material were lost as hydrogen chloride. recovering dissolved catalyst from the reaction The liner contents consisted of lumps of a white products often can be eliminated. solid in the bottom of the liner with a hollow The process of my invention may be carried cylinder of similar material resting on the lumps out in batch operation by placing a quantity of 10 and asmall amount of white crystalline sublimate the catalyst in a reactor equipped with a stirring at e p of e liner. There was a strong device, adding the phenolic compound, heating drogen chloride odor. The liner was out Just or cooling to the reaction temperature, slowly above the hollow cylinder and the hollow cylinder adding the alkylating agent while mixing the contogether with the lumps that were in the bottom tents of the reactor, and recovering the product. 5 of the liner were rapidly ground in a mortar and However, the preferred method of operation is of stored in a glass stoppered bottle. the continuous type. In one mode of continuous operation, the granular catalyst, either alone or EXAMPLE II on a carrier, may b placed in a reaction chamber I and preheated mixtures of the phenolic compound AppqTatus'T250 3 neckeq flask with a draw and the alkylating agent passed through the eqmppgd Wlth stop cock i the fitted catalyst bed. If desired, a quantity of the hydrot remix condenser 90 cahbmted gen halide corresponding to the catalyst may be cypndncal droppmgfunnel mercury sealed charged to the reaction zone as a promoter. The stirrer. 9 22 and a 7 vacuum jack products from Such a treatment may be continw 25 eted spiral wire filled column and a 100 cc. Claisen ously fractionated to separate the unreacted subflask stances from the desired products Procedure-Tc a vigorously stirred mixture of The reactions herein described usually are cargrams (0'497 mol) of p grams of ried out at temperatures of from about 20 to the catalyst prepared as described m Example about 150 C. and under a pressure of from subg 1573 grams of ciclohgxatne 350 were stantially atmospheric to approximately 100 at- .iropwlse over a 5 mmu e penod a,mlxture mospheres. It ordinarily is preferable to have conslstmg of 1753 grams of lsoamyl' present in the charging stock a molecular excess i i 9 g There was of the phenolic compound over the alkylating emperz? ure use a ter on y 'f of the agent in order to minimize Side reactions saturates were 1n, but finally the reaction temper- The following examples are given to illustrate attire fell to .that of The reaction the method of preparing the catalyst and the mixtur was stirred an additional hour at approxresults obtained by the use of the present process, fi f I i g the tenperature s although the data presented are not introduced reused m mmu es 0 p ept at 7M0 with the intention of unduly resricting the gen- 40 for another hour- At thls pomt 50 of Water erany broad scope of the invention: was added to decompose the catalyst. The phenols were separated from other organic ma- EXAMPLE I terials by solution in excess 30% NaOH and by A catalyst was prepared as follows: removal of the hydrocarbon layer and were re- 20.64 grams mol) of bal1 mill ground, C. P. covered by acidification of the aqueous layer with boric acid and 133.52 grams (1.0 mol) of fresh excess concentrated HCl. The crude phenols C. P. anhydrous aluminum chlorid were intiwere extracted with ether; the extracts washed mately mixed by rotating in a mill equipped with with water, NaHCOs and water and dried over agate balls for 1.23 hours. 36.69 grams of the Na2SO4. The combined ether extracts were fracrecovered mixture were transferred to an 850 cc. tionated first at atmospheric pressure and finally glass bomb liner and heated in a rotating steel at reduced pressure. The analytical data are bomb at 200 C. for 1 hour under an initial nitroshown in the following table.

Table I At .h' D't'llti c td Cut No. ggi g: i i e s sgreg a Physical State iggg gggg R gc jvsefy, Remarks d 38.60 ....do Ether and some water. 12.34 do 53.95 3.55 Zliquidphases 9.73 Yellow liquid E133 tiltt it 21-75 Phenol- 3.07 .-..do Yes,inoo 1.38 Yes, in hot 1.83 d 9.30 g. g? p-temyl phenol. 14 1515s 16-91 Bottoms 3. 48 3. (8

. Grams Corrected sum of all cuts+bottoms after cut #2 111.69 Weight of flask contents after cut #2 111. 76 111.69 Unacoounted for 0. 07

The results may be summarized as follows:

Sum of all fractions from out to bottoms inc. 57.74

Unaccouuted for 6.69

Theoretical yield on i-CcHro charged ams..- 41.3 huts #iii to #14 inclusive do..- 26.2 Yield ..per cent.- 63.5

I claim as my invention:

1. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with a compound capable of yielding a hydrocarbon radical at condensation conditions in the presence of a catalyst prepared by reacting boric acid and a metal halide of the Friedel-Craits type with the evolution of hydrogen halide.

2. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with an alkylating agent at alkylating conditions in .the presence or a catalyst prepared by reacting boric acid and a metal halide of the Friedel-Crafts type with the evolution or hydrogen halide.

3. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with an olefinic hydrocarbon at alkylating conditions in the presence of a catalyst prepared by reacting boric acid and a metal halide of the Friedel-Craits type with the evolution of hydrogen halide.

4. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with a monoolefln at allsylating conditions in the presence of a catalyst prepared by reacting boric acid and a metal halide oi the Friedel-Crafts type with the evolution oi hydrogen halide.

o. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with a monoolefin containing more than two carbon atoms per molecule at alkylating conditions in the presence of a catalyst prepared by reacting boric acid and a metal halide of the Friedel-Crafts type with the evolution of hydrogen halide.

d. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with an isoolefin at alkylating conditions in the presence of a catalyst prepared by reacting boric acid and a metal halide of the Friedel-Crafts type with the evolution of hydrogen halide.

"l. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with an isoamylene at alkylating conditions in the presence of a catalyst prepared by reacting boric acid and a metal halide of the Friedel-Crafts type with the evolution of hydrogen halide.

d. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with a mineral acid ester at alkylating conditions in the presence of a catalyst prepared by reacting boric acid and a metal halide of the Friedel-Crafts type with the evolution of I hydrogen halide.

9. A process which comprises reacting a phenolic compound containing a substitutable 'hydrogen atom attached to the rin with an alkyl halide at alkylating conditions in the presence of a catalyst prepared by reacting boric acid and a metal halide of the Friedel-Crafts type with the evolution of hydrogen halide.

10. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with an alkyl chloride at alkylating conditions in the presence of a catalyst prepared by reacting boric acid and a metal halide oi. the Friedel-Craits type with the evolution of hydrogen halide.

11. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with a tertiary alkyl chloride at aikylating conditions in the presence of a catalyst prepared by reacting boric acid and a metal halide of the Friedel-Crafts type with the evolution of hydrogen halide.

12. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with tertiary butyl chloride at alkylating conditions in the presence of a catalyst prepared by reacting boric acid and a metal halide of the Friedel-Crafts type with the evolution of hydrogen halide.

13. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with an alkylating agent in the presence of a catalyst prepared by reacting boric acid and aluminum chloride with the evolution of hydrogen chloride.

14. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with an olefinic hydrocarbon in the presence of a catalyst prepared by reacting boric acid and'aluminum chloride with the evolutionof hydrogen chloride.

15. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with a monoolefin in the presence of a catalyst prepared by reacting boric acid and aluminum chloride with the evolution of hydrogen chloride.

16. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with a monoolefin containing more than two carbon atoms per molecule in the presence of a catalyst prepared by reacting boric acid and aluminum chloride with the evolution of hydrogen chloride.

17. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with an isoolefin in the presence of a catalyst prepared by reacting boric acid and aluminum chloride with the evolution of hydrogen chloride.

18. A process which comprises reacting a phenolic compound containing a substitutable hydrogen atom attached to the ring with an isoamylene in the presence of a catalyst prepared by reacting boric acid and aluminum chloride with the evolution of hydrogen chloride.

JULIAN M. MAVITY.

No references cited. 

